Relay



Nov. 17, 1959 P. N. MARTIN RELAY Filed Feb. e, 1958 'of the relay frame.

United States Patent O i RELAY Paul N. Martin, Frederick, Md., assignorto Consolidated Electronics Industries Corp., a corporation of DelawareApplication February 6, 1958, Serial No. 713,751

'5 Claims. (Cl. 200-87) This invention relates to electro-magneticrelays and to an improved retaining spring and armature arrangement thatallows the amature of the relay to be slipped into position easily andheld there with a minmum of adjustment.

The general configuration of the type of relays to be discussed in thefollowing speciication includes a magnetizable core, a frame holding thecore, a coil surrounding the core, and an armature supported on theframe by a pivot adjacent to one end of the core. When the coil isenergized, it creates a magnetic field in the core, and this eldattracts the armature, causing the latter to pivot on its support. Meansactuated by the armature are arranged to apply pressure to movespring-mounted contacts to engage and disengage the latter with fixedcontacts.

More particularly the armature of the present invention is provided atone edge with bent-over extensions which t around and are pivoted on arather sharp edge The armature is held in place against this edge bymeans of a spring having one portion which is clamped to the frame. Thespring extends over the edge on which the armature is pivoted by adistance greater than the length of the bent-over extensions and fitsaround the extensions so as to press on the edge of the armatureadjacent to the extensions. A second portion of the spring extends fromthe first portion and terminates in a third portion that extends backtoward the first portion. This third portion bears against one surfaceof armature in such a way that the armature is held against the edge ofthe frame but is not subjected to rotational forces of sufiicientmagnitude to affect pivoting of the armature. The reason for having thefirst portion of the spring extend out from the pivot edge by thedistance mentioned is to allow the third portion, which bears on thesurface of the armature and which, because of its length and the lengthof the second portion is very flexible, to be exed suiciently to allowthe bentover extensions to slip past the pivot edge and hook over theframe without bending the first portion of the spring enough to take apermanent set. One of the objects of the invention is to provide animproved relay armature and retaining spring arrangement which willallow the armature to be inserted after the coil and core of the relayhave already been attached to a frame and which will allow the armatureto be pivoted substantially free of undesired rotational forces causedby the spring. Other objects will be indicated in the followingspecification together with the drawings in which:

Fig. 1 is a perspective view of a relay incorporating the invention;

Fig. 2 shows the armature-locating spring of Figs. 1 and 2; and

Fig. 3 is an enlarged cross-sectional view of another relay using thearmaturedocating spring arrangement of Fig. 1.

The relay in Fig. 1 is built around an L-shaped frame Patented Nov. 17,1959 11 of ferromagnetic material such as soft magnetic steel, forexample. A magnetizable, or ferromagnetic, core 12 is attached to theframe and a coil 13 is wound upon or placed upon the core 12. An`armature 14 of soft steel or the like is hinged upon the rather sharplyrounded edge 16 of frame 11 by means of a pair of extensions 17 and 18which are bent to conform to the rather small radius of edge 16.Preferably edge 16 is smoothed off so as to remove any burrs so that thearmature 14 may pivot freely thereon.

Extending from the main part of armature 14 is a pair of arms 19, onlyone of which is visible. In this embodiment both of these arms are moreor less perpendicular to the main part of armature 14 and are thereforeapproximately parallel to the core 12. The ends of the arms rest onstops 21 that are suspended stirrup-like from frame 11, and a thin, leafspring 22 presses the arm 19 against the stop. The purpose of spring 22,is to bias the `arms downward and the main part of armature 14 away fromthe core 12 except when the magnetic iiux induced in the core by anenergizing current in coil 13 pulls the main part of armature 14 againstthe end of core 12, thus pivoting the armature on its axis at the edge16 of frame 11. When the armature is thus pivoted, the end of arm 19rises from stop 21 and pushes on the lower end of an actuating rod 23,which is usually made of insulating material.

Rod 23 is attached to the underside of the middle, resilient blade 24 ofa Contact pile. Two such piles are shown in the present embodiment andeach has three contact `blades of which blades 24 are the movable onesand blades 26 and 27 are relatively stationary. There can, of course, bemany more blades if the piles are made higher, but the simple structureshown includes the basic elements. Each of the movable blades 24 carriesa contact 28 on its upper side and another contact 29 on its lower side,while blades 26 and 27 carry contacts 31 and 32 respectively. In theunenergized condition contacts 29 are pushed down against contacts 31 toform a connection between blades 24 and blades 26. The downward pressureof contacts 29 may be obtained by the set of the blades 24 or byauxiliary springs (not shown). The blades 24-27 are insulated from eachother and from the frame 11 by insulating blocks 33. Each pile of blocksand blades is topped by a metallic end block 34 and is aixed to theframe 11 by a pair of screws 36.

The armature 14 is held against edge 16 by a spring 37 which is shown byitself in Fig. 2. In this embodiment the spring consists of a resilientmetal strip, one end 38 of which has four holes to permit the screws 36to pass through. Adjacent to this apertured end the spring is dividedinto two parts 39 and 40 for reasons later to be considered. Both parts39 and 40 include bent-down intermediate sections 41 and 42,respectively, which are approximately perpendicular to the end 38. Parts39 and y40 are joined together again by a section 43 which is bentupward at an acute angle to the intermediate sections 41 and 42.

Returning now to Fig. 1, it can be seen that the spring 37 is clamped inplace by the contact piles and directly by pressure of the central bodysection 44 of stop 21. It can also be seen that a long strap 45 extendsfrom the central section and is bent down over the armature 14 in thespace between sections 39 and 40 of spring 37. This is one of thereasons the spring was divided into two sections. The purpose of thisstrap is to prevent the armature 14 from moving away from frame 11 farenough to allow the bent-over extensions 17 and 18 to slip free of theedge 16. If the extensions were to do so, they might fall below thelevel of edge 16, thereby making the relay inoperative since armature 14could no longer pivot in response to a magnetic eld induced in the core12.

For this reason the strap 45 must project out beyond the surface ofarmature 14 by an amount less than the length of extensions 17 and 18,measuring this length on the under surface of the extensions, i.e., thesurface in contact with frame 11. However, in order to allow thearmature 14 to be inserted in place after the contact piles and spring37 have already been attached to the frame 11, the end of strap 45should initially be in the position indicated by the dotted lines. Afterthe armature 14 is in place, the strap can be bent into its nal positionwithout injuring the spring 37 or any other parts of the relay.

In order to slip the armature 14 into place, the lowermostpart ofsections 41 and 42 are pulled outward, away from frame 11. The arms 19may then be slid in between stop 21 and spring 22 and the main sectionof armature 14 lifted upward. Since the spring 37 ts between thebent-over extensions 17 and 1S and does not conilict with them, it isnot necessary to bend the spring 37 upward in regions 39 and 40, aswould be required if the sections 41 and42 and 43 were not so long andresilient. Once the upper edge of armature 14 is tucked under section43, it is unnecessary to continue to hold the lower ends of sections 41and 42. The armature can be slid upward, holding it away from frame 11until the extensions 17 and 18 have cleared the pivot edge 16.

In thus holding the armature 14 away from the frame 11, section 43 ofthe spring will be compressed toward sections 41 and 42 and the lattersections may be deflected slightly outward, but, due to the length ofall of these Y sections, at no place is the stress so great as to causeany part of spring 37 to take a permanent set.

One of the advantages of inserting the armature last is that the end 52of the core 12 can be ground to the same plane as the end of frame 11 soas to provide optimum conditions in the working armature air gap.Another advantage is that core 12 can be riveted to the other end offrame 11, thereby assuring excellent contact between the core and theframe so as to reduce the reluctance of the magnetic path.

The relay in Fig. 3 has the same armature retaining spring 37 as isshown in Figs. l and 2. This spring cooperates with the armature exactlyas in Fig. l, and relations between the spring and armature of Fig. 3are equally applicable to those of Fig. l. However, because of thedifferent mode of operation of the contacts, many of the elements ofFig. 3 that perform the same function as corresponding elements of Fig.l are not given the same reference characters but are given characterswhich diier by one hundred.

In the structure of Fig. 3, the end 38 of spring 37 is clamped againstthe frame 111 by means of screws 136 and the two parts 39 and 40 (onlypart 39 is shown in Fig. 3) extend over the upper edge 46 of the mainpart of armature 114. The dimensions of the parts are such that section43 of the spring is compressed against the surface of armature 114 andis approximately parallel to the intermediate section of the spring. Asis indicated by an arrow 47, pressure between armature 114 and spring 37is concentrated primarily at the end of section 43, which is just aboutin line with the sharply rounded pivot edge 116. The pressure of section43 thus forces yarmature 114 against its pivot, but, since spring forceis applied nearly in line with the pivot axis, the spring 37 does notmaterially aiect movement of the armature. In addition, since sections41 and 43 of spring 37 are rather long, they may be made quite exiblewithout unduly reducing the force applied against armature 114.

In order to insure that the armature is pressed downward against edge116, as well as being pressed inward, the upper edge 46 `of armature 114may extend slightly above the upper level of frame 111. The pressure ofspring 37 against edge 46 will force the lower surface of extension 118to rest on the upper surface of frame 111. This force is indicated by anarrow 48, and the resultant of the latter with the force applied bysection 43 of spring 37 is indicated by an arrow 49. Arrow 49, as may beseen, passes very close to the center of curvature of edge 116 and thushas but little torque effect on the movement of armature 114.

As in the case of the relay in Fig. 1, armature 114 may be insertedafter spring 37 has been attached to the frame 111 of the relay. A11that is required is to insert the upper edge 46 of armature 114 over thelowermost part of section 41 of the spring and then push the armature114 straight up, compressing section 43 of the spring against section 41so as to allow the hooks 11S to clear the edge of frame 111. When thearmature 114 has been pushed up far enough to allow the hooks 118 toslip over the edge 1176, pressure of section 43 of the spring will forcethe armature into place against edge 116 and will hold it there asdescribed. It will be noted that there is no need to flex the uppersections 39 and 40 of the spring because of the fact that these sectionsiit in between the hooks 118 and as a matter of fact it is almostimposisble to i'lex sections 39 and of the spring to any great degreewithout causing those sections to be permanently bent, i.e., to acquirea set which would prevent these sections from pressing downward on edge46 of the armature 114 as desired. Practically vall of the ilexing ofspring 37 that need be done is done by sections 41 (and 42) and 43 whichare relatively long and which can be moved a relatively large distancewithout being bent enough to take a permanent set.

The relay in Fig. 3 is provided with a novel contact actuating mechanismto `allow the contacts to be placed at the end of the coil instead of ontop of it. In order to do this a channel 53 is formed in the core 112and an actuating pin 54 is placed in the channel. One end of pin 54 isthreaded and tted with a contact actuating disk 56, which is usuallymade of insulating material. A compression spring 57 pushes on the disk56 to force the other end of pin 54 against the armature 114. Spring 57in turn is held in place by means of a plate 58 which is attached to theframe 111 by any convenient means. In the embodiment shown theattachment means consists of several posts 59 which extend from the edgeof frame 111 and are bent at right angles thereto and staked into plateS8. Only two contacts 61 and 62 are shown, although many more suchcontacts can be provided, if desired. These contacts are supported byslightly exiblemembers 63 and 64 respectively which in turn aresupported by pins 66 and 67 hermetically sealed by glass-to-metal sealsin the plate 58.

When coil 113 is energized, it induces a magnetic iield in core 112 thatattracts armature 114, causing the latter to pivot on edge 116. Thelower end of the armature pushes pin 54, compressing spring 57 andcausing disk 56 to press upon the ilexible member 63 and so forcecontact 61 against contact 62. Due to the short lengths of members 63and 64, their mechanical resonance can easily be made very high comparedto that of the blades 24, 26, and 27 in the embodiment in Fig. l and sothe embodiment in Fig. 3 is especially adapted for use in places whereit will be subjected to high-frequency, mechanical vibrations, although,of course, its use is not limited to just such applications.

What is claimed is:

l. A relay comprising a frame; an armature pivotably mounted on one edgeof said frame said armature having a main portion and extensionsextending at approximatelyY a right angle to the surface of saidarmature facing said frame and in the direction of said frame to form,with said surface of said armature, a groove, said extensions beinghooked over said edge, and a spring to hold said armature in placeagainst said edge with said edge resting in said groove said springhaving a iirst portion attached to said frame at a point removed fromsaid edge and extending beyond said edge, a second portion on the sideof said armature away from the point of attachment of said spring tosaid frame, and a third portion which extends back in the direction ofsaid first portion and presses resiliently against said armature in aregion where the force of said spring on said armature exerts asubstantially torque-free force on said armature by pressing saidarmature substantially directly against said edge of said frame.

2. A relay comprising a frame; an armature pivotably mounted on one edgeof said frame said armature having a main portion and extensionsextending at approximately a right angle to the surface of said armaturefacing said frame and in the direction of said frame to form, with saidsurface of said armature, a groove, said extensions being hooked oversaid edge; and a spring to `hold said armature in place against saidedge with said edge resting in said groove, said spring having a firstportion attached to said -frame at a point removed from said edge andextending beyond said edge and pressing resiliently upon an edge of saidarmature to hold said extensions against the edge of said frame in onedirection, a second portion on the side of said armature away from thepoint of attachment of said spring to said frame, and a third portionwhich extends back in the direction of said first portion and pressesresiliently against said armature in a region where the resultant forceof said rst and third portions of said spring on said armature exerts asubstantially torque-free force on said armature by pressing saidarmature substantially directly against said edge of said frame.

3. A relay comprising a frame; an armature pivotably mounted on one edgeof said frame said armature having a main portion and a pair ofextensions extending from an edge thereof at approximately a right angleto the surface of said armature facing said frame and in the directionof said frame to form, with said surface of said armature, a groove,said extensions being hooked over said edge; and a spring to hold saidarmature in place with said edge of said frame resting in said groove,said spring having a first portion attached to said frame at a pointremoved from said edge of said frame and extending therebeyond andpressing resiliently upon an edge of said armature between saidextensions to hold said extensions against the edge of said frame in onedirection, a second portion on the side of said armature away from thepoint of attachment of said spring to said frame, and a third portionwhich extends back in the direction of said first portion and pressesresiliently against said armature in a region where the resultant forceof said rst and third portions of said spring on said armature exerts asubstantially torque-free force on said armature by pressing saidarmature substantially directly against said edge of said frame.

4. A relay comprising a magnetizable frame consisting of a base sectionhaving a sharply-rounded edge at one end thereof, the other end of saidframe being bent at a right angle to said base section to form a secondsection; a magnetizable core having one end riveted to said secondsection and extending parallel to said base section, the end of saidcore terminating in the same plane as said sharply rounded edge; anarmature comprising a main section pivoted on said edge and extendingover the end of said core, said armature having a pair of extensionsextending from one edge of said main section and bent over atapproximately a right angle to t around the rounded edge of said frame,said edge of said main section extending slightly above the level of therounded edge of the base section of said frame, said armature alsohaving a pair of arms extending from opposite sides of said main sectionand approximately perpendicular thereto; a spring comprising a datresilient member aixed to the base section of said frame at a pointremoved from said rounded edge and extending over said edge of the mainsection of said armature and exerting pressure thereon, said springhaving a bent-down section extending approximately parallel to thesurface of the main section of said armature, and a return-bent sectionapproximately parallel to said surface of said armature and exertingpressure on said surface, the distance between said rounded edge of saidframe and said bent-down section being greater than the length of saidextensions, the resultant force developed by the pressure exerted on thesurface of said armature and the pressure exerted on the edge thereofbeing in a direction such as to pass close to said rounded edge of saidframe so as to hold said armature in place against said rounded edgewhile exerting a minimum torque on said armature.

5. A relay comprising a magnetizable frame consisting of a base sectionhaving a sharply rounded edge at one end thereof, the other end of saidframe being bent at a right angle to said base section to form a secondsection; a magnetizable core having one end attached to said secondsection and extending substantially parallel to said base section; achannel extending through said core and through said second section; anarmature comprising a main section pivoted on said edge of said frameand extending over the end of said core, said armature having a pair ofextensions extending from one edge of said main section and bent over atapproximately a right angle to t around the rounded edge of said frame,said edge of said main section extending slightly above the level ofsaid rounded edge of said frame; a spring affixed to said base sectionat a point removed from said rounded edge and extending over said edgeover the main section of said armature and exerting pressure thereon toforce said extensions against said frame in one direction, said springhaving a bent-down section located beyond said edge of said frame by adistance at least substantially equal to the length of the under side ofthe bent-over portions of said extensions and extending approximatelyparallel to the surface of the main section of said armature, and areturn-bent section extending approximately parallel to said surface ofsaid armature and exerting pressure thereon approximately perpendicularto the pressure on said edge of said main section, the resultant forcedeveloped on said armature being directed to pass close t0 said roundededge so as to hold said armature in place against said rounded edgewhile exerting a minimum torque on said armature; a rod extendingthrough said channel, one end of said rod being located in the path ofmovement of said armature; resilient means urging said rod toward saidarmature; and a pair of contacts including a relatively fixed contactand a relatively exible contact located to be engaged by said rod.

References Cited in the le of this patent UNITED STATES PATENTS

